TSPluginInit() must be defined by all plugins. Traffic Server
calls this initialization routine when it loads the plugin and sets
argc and argv appropriately based on the values in
plugin.config.

argc is a count of the number of arguments in the argument vector,
argv. The count is at least one because the first argument in the
argument vector is the plugins name, which must exist in order for
the plugin to be loaded.

TSPluginRegister() registers the appropriate SDK version specific in
sdk_version for your plugin. Use this function to make sure that the
version of Traffic Server on which your plugin is running supports the plugin.